An RFID system uses tags (or labels) attached to the objects to be identified. Two-way radio transmitter-receivers, called interrogators or readers, send a signal to the tag and read its response.
RFID tags can be passive, active or battery-assisted passive. An active RFID tag has an on-board battery and periodically transmits its ID signal. A battery-assisted passive (BAP) RFID tag has a small battery on board and is activated when in the presence of an RFID reader. A passive RFID tag is cheaper and smaller because it has no battery; instead, the tag uses the radio energy transmitted by the reader. However, to operate a passive tag, the passive tag must receive a radio transmission with a power level roughly one thousand times stronger than that required for signal transmission. Such transmission requirement creates significant comparative differences in terms of interference and exposure to radiation.
Tags may be read-only, having a factory-assigned serial number that serves as a key to a database, or may be read/write, where object-specific data can be written into the tag by the system user. Field programmable tags may be write-once/read-multiple; “blank” tags may be written with an electronic product code by the user.
RFID tags contain at least three parts: an integrated circuit for storing and processing information that modulates and demodulates radio-frequency (RF) signals; a means of collecting DC power from the incident reader signal; and an antenna for receiving and transmitting the signal. The tag information is stored in a non-volatile memory. The RFID tag includes fixed or programmable logic for processing the transmission and sensor data.
Normally, the RFID sensing system has an antenna provided to generate a field effect. With the field effect, whenever an object passes through the field and creates a disturbance in the field, a microelectric charge is induced to indicate that an object passes through the field. If the field coverage is wide enough, then the detection result might be sufficient to provide an accurate result to the hosting party. However, current commercially available sensing systems do not fulfill the requirements to do so.
This Discussion of the Background section is provided for background information only. The statements in this Discussion of the Background are not an admission that the subject matter disclosed in this section constitutes prior art to the present disclosure, and no part of this Discussion of the Background section may be used as an admission that any part of this application, including this Discussion of the Background section, constitutes prior art to the present disclosure.